Digital content can be stored in a content repository. Content items in a content repository can be organized using a taxonomy that includes tags identifying categories for the content. A taxonomy can include a classification of content items into categories.
The number of content items grouped using tags can greatly exceed the number of tags used to organize the content items. For example, a large number of content items, such as web pages, may be grouped into a small number of categories, represented by tags. Thus, the number of content items (i.e., web pages) can be much larger than the number of tags (i.e. categories). Moreover, the content items can be modified more frequently than the tags of the taxonomy. For example, content items such as web pages may be modified on a daily or weekly basis, while a group of tags may be modified when existing categories are no longer effective for organizing the information. Furthermore, content items and tags may be respectively managed by different entities with different access rights. For example, to ensure that the categories used to organize content items remains predictable over time, the ability to modify tags representing the categories may be restricted to a small number of entities, such as “librarians.”
As a result, organizing content using tags can present challenges. Because the number of content items greatly exceeds the number of tags, storing references to tags in the metadata of a content item can often be more efficient than storing references to content items in a tag. However, having different access mechanisms for the tags and for the content items can prevent content items from being updated to reflect changes to the tags, thereby undermining the organization of content in the content repository. Furthermore, modifying content items to reflect changes to the tags can require processing-intensive searches and updates of large numbers of content items.